Nine common mistakes destroy lead generation businesses, organized into three tiers: fatal, expensive, and growth-stalling. The fatal tier includes TCPA compliance negligence (average class action settlement $6.6M, with 67% increase in 2024 cases and 112% jump in Q1 2025), under-capitalization causing the cash flow crunch (82% of business failures stem from cash flow issues), and single buyer dependency creating dangerous concentration risk where 50%+ revenue from one buyer transforms you into an outsourced marketing department. These failures are predictable and documented, with professional plaintiffs maintaining dozens of phones to generate lawsuits, making TCPA litigation a business model itself. Prevention requires consent documentation via TrustedForm certificates retained for five years, pre-contact scrubbing against litigator lists, maintaining six months of operating expenses plus 20% buffer, and diversifying buyer relationships before crisis hits. The key insight is that every lesson learned cost someone else millions of dollars, making pattern recognition essential for survival.